"Burst" lip is correct in that the neck is drawn out so thin that the glass bursts leaving a thin, ragged edge. Such a bottle is blown in a "blow-by" or "blow-back" mold. This is a British technique to produce cheap bottles that don't need any lip finishing.sgyouk said:I think that is called a "sheared" lip. I have a couple of ink bottles of the same type.
Really cool bottle!!!